Control of electrically-operated switches.



H. E. WHITE,

CONTROL OF ELBGTRIGALLY OPERATED SWITCHES. APPLIOATION FILED r212. 27,1909.

969,738. Patented Sept. 6, 1910.

2 SHEETS-SHEET l.

FORWARD l Yrgzvzzs .E' ZZSZYENTUR flq- ,a/ H/IRQLI? EZ WHITE.

ITTEK H. B. WHITE. CONTROL OF ELEGTRIGALLY OPERATED SWITCHES.

APPLIO'ATION FILED 313.27, 190s.

Patented Sept. 6, 1910.

2 SHEETS-SHEET 2.

l ZIZIZZ'JYESSE INYENTDH HAROLD Z7. 'SZSZEIZTE. W

UNITED STA1EATEN HAROLE 1E. WHITE, 01? SCI-IENECTAID Y, NEW YORK,ASSIGNOR TO GENEREL ELECTRIC COMPANY, A CORPORATION 01 NEW YORK.

Specification of Letters Patent.

Patented Septrii, 1939.

Application filed February 27, 1909. Serial No. 489,481.

To all whom it may concern:

Be it known that I, HARoLn E. Wnrrn, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in the Control ofElectrically op ated Switches, of which the following is aspecification.

My invention relates to the operation and control of electricallycontrolled switches, d particularly to the operation succesely in acertain order of a plurality of ch switches. It is especially useful inwrrnection with systems of motor control 1 which a. plurality ofelectrically con- .olled switches or contactors are arranged operate insuccession to increase step-l.)y top the vol age applied to the motor.Ariangements or this kind are employed in starters for electric motorsand have been so arranged that, by closing a single masterswitch,contactors are caused to operate automatically in. succession to cut outsection by section the resistance interposed in the motor circuit onstarting, or in some other way to increase stepby-step the voltageapplied to themotor. Similar arrangements have also been used in systemsof motor controlin which the master-swit3h has a plurality of onpositions and serves to regulate the operation of a series ofcontactors, the arrangement being such that the master-switch may eitherdirectly control the operation of the coutactors one at a time, or maycause a number, or all of them, to operatautomatically in succession. Tn

such systems of control it is desirable that.

a certain time interval, the length of which depends upon the conditionsof service, should elapse between the operation of successive resistancecontrolling contactors. It is also often desirable that the rate of sucscessive operation of these contaclors depend,

to a certain extent, upon the current in the motor circuit; that is,that the operation- F resultinp therefrom, has taken place.

rality of electrically controlled switches covered in a jointapplication by Eugene R1 Carichofi' and myself, Serial No. 480,488,filed February 27, 1909. In systems of control of this type, in the caseboth of those ctpitactors which initially complete the motor circuit andthose contactors which cut out section by section 'the resistance inter=posed in the motor circuit on starting, the magnetizing coil of thecooperating auxiliary switch receives its increased current only afterthe contactor has actually closed. It may ha pen, therefore, in somearrangements hat a contactor, during the first part of its closingmovement, will allow the auxiliary switch to move in a closing directionto a certain extent before the increase of current, due to closing ofthe contactor, has taken place in the magnetizing coil of theclectromagnet ot' the.auxiliary switch. Under some conditions this mayrender the control of the auxiliary" switches by their electromagnetssomewhat uncertain.

I one aspect, my invention relates to systems or control of the generaltype covered by the joint application above referred to, and comprisesmeans for maintaining the auX- iliary switch substantially at restduring the initial movement of the contactor, that is, until the circuitclosed by the contactor has been made, and the increase of currentin themagnetizing coil of the auxiliary switch y my invention I insure thatthe closing of an auxiliary switch is always subject to the control ofits electromagnet.

in another aspect my invention relates to a new and improved form ofauxiliary switch attachment for use with electrically controlledswitches and systems of control oif'this type.

Other objects and features of my invention will hereinafter appear andwill be particularly pointed out in the appended claims.

In the parsimilar embodiment of my invention which I have illustratedherein, the ineans for maintaining the auxiliary switches substantiallyat rest comprises means for causing the magnetization of theelectromagnet which controls the closing of an auxiliary switch to begreat enough, during the time that its contactor is closing and thechange of conditions in the power or motor circuit resulting therefromis taking concurrently with the increase in magnetizswitch arrangementused on the resistance ing coil, "ooperating with the coil which isreleased by the closing of its corresponding the number of effectiveturns in the electromagnet, due to the-change of conditions in latterarrangement in connection with the elevation, partly in section, showingthe place, to maintain the auxiliary switch open, provision being madefor rendering this means ineffective after the contactor has closed. Inthe particular arrangements shown, either I provide a secondmagnetizenergized from the power or motor circuit, for the magnet whichcontrols the closing of an auxiliary switch after the same has beencontactor, said second coil being deenergized upon the closing of saidcontactor; or I arrange connections with" the magnetizing coil which isenergized from the power or motor circuit, such that the correspondingcontactor in closing shunts a portion of said magnetizing coil. withsuch arrangements,

magnet which controls the closing of an auxiliary switch, is greaterbefore the closing of its corresponding contactor than afterward, andthe reduction takes place ing current in some of the turns of said thepower or motor circuit resulting from the closing of that contactor. Imay use either one or both of the. above named arrangements in a systemof motor control although, for reasons which will hereinafter appear, Iprefer to use the first arrangement in .connection with those contactorswhich initially complete the motor circuit and the resistancecontrolling contactors.

In themliawings, Figure 1 illustrates diagraimnaticallya system of motorcontrol having my invention incorporated therein; Fig. 2'is-a-sideelevation, partly in section, of a contactor provided with theauxiliary controlling contactors in'the system shown 1n Fig. 1; F 1g. 31s a front elevation of the device shown 1n Fig. 2; and Fig. 4 is anauxiliary switch attachment used on the line contactors in the systemshown in Fig. 1.

I have shown diagrammatically my invention as applied to a simple systemof motor control for a direct current motor, but this is merelyillustrative and, as will be obvious to those skilled in this art, itmayequally well be applied to other forms of dynamo-electric machineryand to other types .of control; or, in fact, employed in any connectionwhere it is desired to regulate the conditions in a power circuit bymeans of a plurality of switches .operatingin succession.

In the diagrammatic representation which I have employed and' in thefigures which illustrate the mechanical and electrical construction ofthe switches or contactors which effect the connections in the mbtbrcircuits, I have shown contactors which are i netically and those whichare operated electropneumatically or otherwise.

Referring to the drawings, particularly Fig. 1, a source of current isindicated at T, With which the power and control circuits of the systemare connected through a switch S. The armature of the motor to becontrolled is indicated at A and its field at F, the motor in this casebeing a series motor, although other types of motor might equally wellhave been shown. Electrically controlled switches or contactors of anysuitable mechanical construction as, for example, that illustrated inFigs. 2 and 3 and hereinafter described, are indicated at L, L and L Las arranged to connect the motor to the source for either direction ofrotation. A starting hr control resistance is shown as made up ofsections R R R and R which may be short circuited by suitable contactors1, 2, 3 and 4, respectively, the construction of these contactors and oftheir auxiliary switch attachments being shown in Figs. 2, 3 and 4;, andhereinafter described. A master-switch K shown developed in the usualconventional manner, and as of the type in which a drum, provided withsuitable segments cooperates in both directions from off position with aset of fingers a, Z), c, d, e, f, g and h. This master-switch serves toregulate the opera? tion of the contactors for both directions ofrotation of the motor, one direction of movement serving for forward andthe other for reverse operation. i;

Contactors If and L are provided, respectively, with auxiliary switches5 and 6, 7 and S which make certain connections in the control circuits.These auxiliary switches are shown in a well known conventional mannerand may consist of a contact disk which is mechanically connected to themovable element of the contactor and is arranged to bridgetwo fixedc-ortacts when in its lower position and two other fixed contacts whenin its upper position; fro-m the drawing it will be clear that theswitches 5 and 7 are closed when the contactors L and L are open, andare open when said contactors are closed, while the switches G and 8 areopen when the con- .tactors are open and are closed when the coarse willljmore fully cxplaincd in connection with 3 and -l in which they areillustrated. These auxiliary switches are denoted in Fig. l by thecharacters 1O, 11, 12, 13 and 14-. Briefly stated, these auxiliaryswitch attachments comprise fixed contacts which are bridged by acontact dislr of usual form, to which is secured a core of magneticmaterial having extending upwardly from it a rod which at its upper .endis engaged by a part of the movable member of the contactor, beingthereby held in its raised position when the contactor is open apdpermitted to fall when the con tactor is closed. Said core is arrangedto move in the field of an electromagnet, the energization of whichdepends upon the current. in the motor circuit. in the case of theauxiliary switch attachments to the contactors L and L shown in Fig. 4,the electromagnet is provided with two coils, one a coil 15 or 16arranged in the motor circuit, and the other a coil 17 or 18 connectedinone of the control circuits, as shown in the drawing and hereinafter described. In the case of the auxiliary switch attachments to theresistance controlling 'contactors l, 2 and 3, the magnetizing coils 19.2t) and 21 are all connected in series in the motor circuit when thesecontactors are open. The coils 19, 20 and 21 each have a connectionleading from some point intermediate its ends, and said coils are soconnected with reference to their corresponding contactors that each ofsaid contactors in closing short circuits a portion oi said magnetizingcoil. as well as the correspondin; section of resistance: the,arrangements of these connections will be clear from Fig. 1.

Referring now to Figs. 2, 3 and l. I will PlUt'tHl to describe theparticular arrangcnicnt o'l" contactor and switch attachments which Ihave found well suited to the 'arrying out of my invention. As far asthe construction of the contactor itself is concerned, that shown inFigs. 2 and 3 is well adapted for all of the contactors used inthesystem of control illustrated. The particular arrangement of magnetizingcoil for the auxiliary switch attachment shown in Figs. 2 and 3corresponds. however, particularly with those attachmentsdiagrammatically illustrated in Fig. 1 in connection with contactors l,and 3. In Fig. t, I have shown how the auxiliary switch magnetof Figs. 2and 3 can be modified to correspond with the arrangement shown in Fig. 1in connection with the contactors L and L Referring to Figs. 2 and 3, 25is a backboard of suit able insulating material, to which is secured acasting 2G by means of bolts 27 and 28 passing through the backboard Tieform of the casting 26 will be apparent from the drawing, it beingunderstood that the cylindrical portion 29 thereof extends outwardly toform the core upon which the actuating coil 30 of the contactor ismeanted, while ears 31 extend outwardly below the coil 30 and receivebetween them the movable armature 32 which is pivoted upon a pin 33extending through the cars 31 and through said armature 82. Angle irons34 bolted to the top of the ends of the cars 31 serve to hold the coil30 on the core 29, while at the same time providing for its easyremoval. Bolted to the armature 32 by bolts 35 is a casting 36 havingears 37 between which, on the pin 38 are pivoted contact fingers 89carrying removable lips 40 of well known form. The pivoted contactfingers 39 are forced in a counterclockwise direction by the s rings 41arranged as shown, heels a2, whic i engage with a shoulder upon thecastin 36, serving to limit the movement; of t e fingers 39 by thesprings 41. The lips 40 cooperate with lips 4:3 removably secured to abracket 46 bolted to the backboard 25 by a bolt 47, as clearly shown.This bracket l6 carries the magnetic blowout coil 48 having the polepieces 49 and 50 embedded in the walls 51 and 52 of an arc chute formedof suitable arc resisting material. This particular construction ofcontactor I do not regard as my invention, and I wish it to beunderstood that many other forms may be employed equally well. Below thecontactor and secured to the backboard 25 are fixed contact members and56 which are bridged by a contact. dish a? of well known form, carriedby a rod 58. The rod 58 carries a core 59 of magnetic material fixed onsaid rod and another core (30 of magnetic material which is adjustableon said rod, being held in any desired position by means of a nut (ll.The cores 5S) and (30 move in the ticld oi? an electroniagnet C01.-posed of a frame. 2 of magnetic material. of the form shown in Fig. 2.which is bolted to the bottom of the frame 20 of the contactor, the coilof the electroinagnet being shown in Figs. 2 and 23 as a single turn ofheavy conductor (33. he core (30 passes freely through ahole in thelower part of the frame (52 and the upper end of the rod 58 passesfreely through a hole in the upper part of said frame, as clearly seenfrom Fig. The holes in the frame (32 may be lined with brass tubing, inany we'll known manaer, to prevent sticking. The upper end of the rod 58carries pinned to it a disk or washer (35, beneath which on each side oithe rod 58 extend heels (:6 projecting from and preferably formedintegral with the armature 3;. The outer turn of the conductor (33 isbolted to the frame ()2 by the bolts (37. by which the frame (52 .ssecured to the frame 26, and the ends of flexible conductors 68 and 69are clamped between the conductor 63 and the frame (32 at. d serve tomake good electrical connection between this point on the coil of theconductor 63 and the movable contact fingers 39, the other ends of theseconductors 68 and 69 being secured 'to these contact fingers as clearlyshown in the drawing and as well understood by those familiar withcontactor construction. As shown in Figs. 2 and 3, the contactor and theauxiliary switch are both closed. In this position the heels 66 are intheir lower position and the rod 58, carrying the contact disk 57, isfree to drop, unless it is held in its raised position by themagnetizing 5 am, closing of the contactor.

Fig. 2.

In Fig. 4: is shown an arrangement of coils for the magnet of'theauxiliary switch attachment of the kind indicated in Fig. 1 inconnection with contactors L and L In this arrangement the field frame62 is similar to that shown in Fig. 2; and the movable parts of theauxiliary switch at tachment, consisting of the cores 59 and 60' mountedon the rod 58, may be exactly the same'as these parts in the arrangementof The coil Which-is energized from the power circuit, may consist ofthree quarters of a turn of heavy conductor 63 arranged as shown, theend of the same being supported and held in good electrical engagementwith the ends of the flexible conductors 68 by means of the bolt 67 asin Fig. 2. Above the heavy conductor 63 is a coil 63" of finer wirewhich co'rresponds to the coils 17 and 18 indicated in Fig. 1 inconnection with conductors L and L It will be obvious to those skilledin this art that the number of turns both of the heavy conductor, whichis energized from the power circuit, and the coil which is energizedfrom the control circuits may be varied to suit particular conditions;and it is also obvious that the field structure of the auxiliaryswitch'attachment may be modified as desired.

The arrangement of motor and control circuits will be clear from thefollowing description of the niode of operation of the system. Theswitch S being closed and the masterswitch K being moved to its firstforward position, a circuit is completed from the side of the source,through the wire 7 5, through the controller fingers a and b and theircooperating segments, to the wire 76, thence through the actuating coilof the contactor L the magnetizing coil '17, actuatingcoil of thecontactor L auxiliary switch 7, through the wire 77 to the side of thesource. The contactors L and L are, therefore, closed and a motorcircuit will be completed as follows: From the side of the source,through the field F, resistance sections R R R R through the whole ofthe magnetizing coils 19, 20 and 21 of the auxiliary switches 12, 13 and14, through the coil 15 of the auxiliary switch 10, through the maincontacts of contactor L armature A, main contactor L to the side of thesource. As long as the masterswitch K remains in its first position nofurther operation of the contactors will take place and the motor willremain connected to the source through all of the resistance.

ond ='forward position, the fingers g and h operating segments and areconnected by them. It will be seen from the diagram that the finger his, by a wire 78, connected through the switch 10 to the wire 76 and,therefore, if the auxiliary switch 10 is closed current will flow fromthe wire 76 through said switch 10, through wire 78, fingers h and g andtheir cooperating segments, wire 79, actuating coil of the contactor 1,and back to the side of the source through the return wire 80, therebycausing the closing of the contactor 1 and the short circuiting of thesection of resistance R The closing of the switch 10, however, is underthe control of the current in the motor circuit, and if this exceeded acertain value at the time the master-switch was thrown to its secondposition, the switch 10 was not closed and the closing of the contactor1 was prevented. In this connection it is to be noted that the coil 17is energized concurrently with the actuating coils of the contactors Land L,

by closing of the switchfi when the contactor L closed, themagnetization furnished by the coil L7 serves to hold the auxiliaryswitch 10 open until the motorcurrent has time to build up and energizethe coil 15. Closing of the switch 10, upon the closing of the contactorL is therefore, prevented be fore the current in the motor circuitbecomes effective in the coil 15.

As long as the master-switch remains in its second position, the linecontactors L and L and the first resistance contactor 1 only will beclosed. In moving the masterswitch to its third forward position, thefinger f comes into engagement with its cooperating segment and isconnected to the wire 78 as was the finger g. A wire 82 leads fronL thefinger f through the auxiliary switch 12 to the actuating coil of theconwire 80 to the side of the source. If, there arebrought intoengagement with their 00- tactor 2, and thence. through the return' Ifthe master-switch K is moved to its sechodimeuts seems V tore, theswitch 12 has closed the cont actor 2 will he closed and the section ofresistance 1 will he sl'iort-circuited. Closing of the switcl 12 takesplace under the control of the motor current in the magnetizing coil l9.it being noted that the switch 1 in closing short circuited not only thesection of resistance R but also a portion of the mag netizing coil 19,the manner in which this is accomplished being clear from the diagramand the foregoing description of the auxiliary switch attachment. Byinitially allowing the motor current to pass through the whole of thecoil 19, the holding of the switch 12 open, until the increase ofcurrent due to short circuiting of the resistance R has taken place, isinsured. It is obvious that further movement of the master-switch in theon direction will result in successively energizing the wires 8?) and 84and closing of the contactors 2E and 4 under the control of theauxiliary switches 13 and 1%,

respectively. l t wiil, of course, be understood that the resistancecontrolling contat-tors l, 2, 3 and t may not only he closed one at atime under the control of the master-switch it, but the master-switchmay, it desired. he thrown inn'nediately to toll on position. whereuponthe closing of the cont-actors will take place auton'iat-ically insuccession under the control of the auxiliary switch attachments whichrespond to the current in the motor circuit and prevent cut ting out o1the resistance too rapidly.

It will he obvious to thosesltilled in this art that my invention may heembodied in a variety of t'orms, and it is m intention to cover in thefollowing claims ali such enias come within the scope of my HH't'llliOH.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. In combination with a power circuit a plurality of contactorsintended for operation in succession to eftect certain connections insaid power circuit, auxiliary switches cooperating with certain ofcontactors each arranged to control the operation of a succeedingcontactor, means for holding each auxiliary switch open while itscoiiperating contactor is open, an electromagnet cooperating with eachauxiliary switch for controlling the closing of said auxiliary switch,and means for maintaining the auxiliary switch substantially at restdarling the closing operation of the coopcrating contactor.

In combination with a power circuit, a plurality of contactors intendedfor operation in succession to etiect certain con nections in said powercircuit. auxiliary switches cooperating with certain of said contactorseach arranged to control the operation ot a succet-zding coutactor,means for holding each auxiliary switch open while its said oration insuccession to eifect certain conncctions in said power circuit, a.plurality of auxiliary switches each arran d to con trol the operationof a contactor, a plurality of electromagnets each cooperating with anauxiliary switch, and connections whereby a 30 contactor in closingweakens the magnetizing effect of the electromagnet of its cooperat ingauxiliary switch.

4. In combination with a power circuit,

a plurality of contractors intended for op- 35 oration in succession toeffect certain connections in said power circuit, a plurality ofauxiliary switches each arranged to control the operation-of acontactor, a plurality of electromagnets each cooperating with aneuxiliary switch, and connections whereby a contactor in closingdecreases the number of etieetire turns in the electromagnet oi itstoiiperating auxiliary switch.

in combination with a a plurality oi contactors intended for op erationin succession. to effect certain connections in ,said power circuit,auxiliary switches cooperating with certain of said contactors eacharranged to control the op- 10o eration of a succeeding contactor, meansfor holding each auxiliary switch open while its cooperating contactoris open, an electro magnet cooperating with each auxiliary switch, inclosing weakens the magnetizing effect of the coil of its cooperatingauxiliary switch.

6. In combination with a power circuit, a plurality of contact'orsintended for oporation in succession to eti'ect certain counections insaid power circuit, auxiliary switches cooperating with certain of saidcont actors each arranged to control the operation of a succeedingcontactor, means for holding each auxiliary switch open while its 116cooperating contactor is'open, an electromagnetcooperating with eachauxiliary switch, and connections whereby a contactor in closingdecreases the number of eficctive turns in the electromagnet of itscooperat- 120 ing auxiliary switch.

7. In combination with a power circuit, a plurality of contactorsintended for operation in succession to eflect certain connection insaid power circuit, a plurality of auxiliary switches each arranged tocontrol the operation of a contactor, a plurality of electromagnets eachat tinged to cooperate with an auxiliary switch, and connections wherebya contactor in closing power circuit, 95

and connections whereby a contactoiglliS shunts a por tion of theelectromagnet of the auxiliary switch which controls the succeedingcontactor.

8. In combination with a power circuit, a plurality of contactorsintended for operation in succession to effect certain connections insaid power circuit, auxiliary switches cooperating with certain of saidoontactors each arra aged to control the operation of a succeedingcontactor, means for holding each auxiliary switch open while itscooperating contactor is open, an electromagnet cooperating with eachauxiliary switch, and connections whereby a contactor in closing shuntsa portion of the electromagnet of its cotiperating auxiliary switch.

9. In combination with a power circuit, a plurality of contactorsintended for operation in succession to efiect certain connections insaid power circuit, a plurality of auxiliary switches each arranged tocontrol the operation of a contactor, a plurality of electromagnets eachcooperating with an auxiliary switch, and connections whereby acontactor in closing weakens the magnetizi'ng effect of theelectromagnets of those auxiliary switches which control said 0011-tactor and the succeeding contactor.

10. In combination with a power circuit, a plurality of contactorsintended for operation in succession to effect certain connections insaid power circuit, auxiliary switches cooperating with certain of saidcontactors, each arranged to control the op eration of a succeedingcontactor, means for holding each auxiliary switch open while itscooperating contactor is open, an electromagnet cooperating with eachauxiliary switch for controlling the closing of said auxiliary switch,and connections whereby a contactor in closing weakens the magnetizingeffect of the electromagnets of those auxiliary switches which controlsaid contactor and the succeeding contactor.

11. In combination with a power circuit, a plurality of contactorsintended foroperation in succession to efl'ect certain connections insaid power circuit, auxiliary switches cooperating with certain of saidcontactors each aranged to control the op-- e 'ation of a succeedingcontactor. means for holding each auxiliary switch open while itscoiiperating contactor is open, an electromagnet cooperating with eachauxiliary switch for controlling the closing of said auxiliary switch,and connections whereby each contactor in closing shunts theelectromagnet of the auxiliary switch which controls said contactor anda portion of the electromagnet of the-auxiliary switch which controlsthe succeeding contactor.

12. In combination with a power circuit. a plurality of contactorsintended for opera tion in succession to efi'ect certain connections insaid power circuit, a plurality of auxiliary switches each arranged tocontrol I the operation of a contactor, a plurality ol' electromagnetseach arranged to cooperate with an auxiliary switch, and connect ionswhereby a contactor in closing both effects the desired connection inthe power circuit and shunts a portion of the electromagnet whichcontrols the succeeding auxiliary switch.

13. In combination with a power circuit, a plurality of contactorsintended for operation in succession to effect certain connections insaid power circuit, a plurality of auxiliary switches each arranged tocontrol the operation of a contactor, a plurality of electromagnets eacharranged to cooperate with an auxiliary switch, and connections wherebya contactor in closing both effects the desired connection in the powercircuit. and shunts the electromagnet cooperating with the auxiliaryswitch which controls that contactor and shunts a portion of theelectromagnet of the auxiliary switch which controls the succeedingcontactor.

14. In combination with a power circuit, a plurality of contactorsintended for operation in succession to ett'ect: certain connee tions insaid power circuit, auxiliary switches each cooperating with a contactorand arranged to control a succeeding contactor, a connection betweeneach contactor and its auxiliary switch whereby when the former is openthe latter isheld open and when the former is closed the latter ispermitted to close, an electromagnet energized from the power circuitarranged to control the closing of each auxiliary switch, and meansllldupendent of the power circuit to be controlled for maintaining eachauxiliary switch open until the closing of its corresponding contactorand until changes in the power circuit due to the closing of thatcontactor have taken place.

a plurality of contactors intended for operation in succession to efiectcertain connections in said power circuit,auxiliary switches eachcooperating with a: contactor and arranged to control a succeedingcontactor. a connection between each contactor and its auxiliary switchwhereby when the former is open the latter is held open and when theformer is closed the latter is permitted to close, an electromagnetenergized from the power circuit arranged to control the closing of eachauxiliary switch, and means for maintaining the magnetization of saidelectromagnet great enough during'the closing of its correspondingcontactor to hold said auxiliary switch open independently of themechanical connection with its contactor, said means being renderedinoperative upon the closing of the contactor.

16. In a system of motor control, a resistance, a plurality ofcontactors intended 15. In combination with a power circuit,

' to control the control circuit ofa succeeding contactor, a connectionbetween each contactor and its auxiliary switch whereby when the formeris open the latter is held open and when the former is closed the latteris permitted to close, an clectromagnet ha ving a magnetizing coilenergized from said power circuit and a second magnetizing coilenergized independently of the power circuit arranged to prevent theclosing of that auxiliary switch cooperating with the first of theplurality of contactor-s it the current in the power circuit exceeds acertain value, means for causing the deenergization of the lastmentioned magnetizing coil upon the closing of the correspondingcontactor, an electromagnet having a magnetizing coil energized fromsaid power circuit arranged to prevent the closing of each auxiliaryswitch cooperating with those contactors other than the first it thecurrent in the power circuit exceeds a certain value, amt

connections such that each of the last mentioned contactor-s in closingshunts a portion of the magnetizing coil of the magnet which controlsthe closing of its auxiliary switch.

23. A system of motor control comprising a motor, a resistance, a linecontactor r'or connecting said motor in series with said resistance, aphirality of contactors intended for operation in succession to cut outsaid resistance section by section, control circuits for saidcontactors, ,auxiliary switches each cooperating with a contactor andarranged to control the .control circuit of a succeeding contactor, aconnection between each contactor and its. auxiliary SWiTCll wherebywhen the former is open the latter is held open and when the former isclosed the latter is permitted to close, an clectromagnet having amagnetizing coil energized from said power circuit and a secondmagnetizing coil energized independently of the power circuit arrangedto pre vent theclosing of the auxiliary switchcooperatingwith"saidline**contactor it the current in the motor circuitexceeds a certain value, means for causing deenergization of the lastmentioned magnetizing coil upon the closing of said line contactor, anelectromagnet having a. coil energized from said power circuit arrangedto prevent the closing of each oi the auxiliary switches cooperatingwith the resistance controlling contactors if the current in the motorcircuit exceeds a certain value, and connections such that eachresistance contactor in closing shunts a portion of the magnetizing coilof the magnet which controls the closing of its auxiliary switch.

24. In con'ibination with a power circuit, a plurality of contactorsintended for operation in succession to effect certain connections insaid power circuit, c0nt rol.circui ts for said contactors, auxiliaryswitches each cooperating with a contactor and arranged to control thecontrol circuit of a. succeeding contactor, a connection between saidcontactor and its auxiliary switch whereby when the former is open thelatter is held open and when the former is closed the latter ispermitted to close, an electromagnct having a magnetizing coil energizedfrom said power circuit and a second magnetizing coil energizedindependently of the power circuit arranged to,

control the closing of said auxiliany switch, and means for causing thedenergization of the last mentioned magnetizing coil concurrently withthe closing of the correspond ing contactor.

25. In combination with a power circuit, a plurality of contactor-sintended for operation in succession to eflect certain. connections insaid power circuit, control circuits for said contactors. auxiliaryswitches each cooi'ierating with a contactor and ar'anged to control thecontrol circuit of a succeeding contactor,a connection between eachcontactor and its auxiliary switch whereby when the former is open thelatter is held open and when the former is closed the latter ispermitted to close. an electromagnet having a magnetizing coil energizedfrom said power circuit arranged to control the closing of saidauxiliary switch, and connections such that each contactor in closingshunts a portion of the magnetizing coil of the magnet which controlsthe closing of its auxiliary switch.

26. In combination with a power circuit, a plurality of contactorsintended for operation in succession to effect. certain connections insaid power circuit, control circuits for said contactors, auxiliaryswitches each cooperating with a contactor and arranged to control thecontrolcircuit of a succeeding contactor, a connection between themovable member of each contactor and the movable member of its auxiliaryswitch whereby when the contactor is open the auxiliary switch is heldopen and when the contactor is closed its auxiliary switch is permittedto close, an electromagnet having a magnetizing coil energized from thepower circuit cooperating with the movable member of each auxiliaryswitch and arranged to control the closing of said switch, andconnections including a connection from a point on said magnet coil tothe corresponding contactor whereby when the latter. is closed a portionof said magnet coil is shunted and its number of effective turns therebydecreased.

27. The combination with a contactor having a. fix d contact member, amovable contact member, an actuating coil for moving said movablecontact member into engagement with said fixed contact member, of anauxiliary switch attachment comprising a fixed contact member, a movablecontact member, a connection between the movable contact member of saidcontactor and the movable contact member of'said auxiliary switchattachment whereby when said contactor is open the contacts of saidauxiliary switch attachment are held open and when said contactor isclosed the contacts of said auxiliary switchattachmenflare permitted toclose, a magnet coil for con rolling the closing of the contacts of theauxiliary switch attachment, and an electrical connection be tween apoint on said magnet coil intermediate its ends and the movable contactmember of said contactor.

28. The combination with a contactor having a fixed contact member, amovable contact member, an actuating coil for moving said movablecontact member into engagement with said fixed contact member, of anauxiliary switch attachment comprising a fixed contact member, a movablecontact member, a connection between the movable contact member of saidcontactor and the movable contact member of said auxiliary switchattachment whereby when said contactor is open the contacts of saidauxiliary switch attachment are held open and when said contactor isclosed the contacts of said auxiliary switch attachmentnre permitted toclose, and a magnet for controlling the closing of the contacts of theauxiliary switch attachment having a magnetizing coil of many turns ofsmall wire and a magnetizing coil of a few turns of large conductor.

29. The combination with a contactor having a fixed contact member, amovable contact member, an actuating coil for moving said movablecontact member into engagementwith said fixed. contact member, of anauxiliary switch attachment comprising a fixed contact member, a movablecontact member, a connection between the movable contact member of saidcontactor and the movable contact member of said auxiliary switchattachment whereby when said contactor is open the contacts of saidauxiliary switch attachment are held open and when said cont-actor isclosed the contacts of said auxiliary switch attachment are permitted to'close, a core of magnetic material connected to the movable contactmember of the auxiliary switch attachment, a second core adjustablyarranged on the same axis as said first mentioned core, and a magnetcoil in the field of which said cores are arranged to move as thecontacts of said auxiliary switch attachment open and close.

In witness whereof, I have hereunto set' my hand this 26th day ofFebruary, 1909.

HAROLD E. WHITE.

Witnesses BENJAMIN B. HULL, HELEN Onrom).

imer in Letters Pate 369,738.

Discla DISCJLWA IMEZIEL 969,7-38.Harold E. White, Schenectady, N. Y.CoN'raoL OF ELECTRIC/ALLY- OPERATED Swrrcnns. Patent dated September (5,1910. Disclaimer filed May 17 1918, by the assignee, General ElectricCompany.

Enters this disclaimer-- As to claims 1 and 19 of said patent, whichclaims read as follows:

1. In combination with a power circuit, a plurality oi contactorsintended for operation in succession to efl'ect certain connections insaid. power circuit, auxiliary switches cooperating with certain of saidcontactors each arranged to control the operation of a succeedingcontactor, means for holding each auxiliary switch open while itscooperating contactor is open, an electi'ornagnet cooperating with eachauxiliary switch for controlling the closing of said auxiliary switch,and means for maintaining the auxiliary switch substantially at restduring the closing operation of the cooperating contactor. i

19. In combination with a .power circuit, a plurality of contactorsintended for operation in succession to efiect certain circuits for saidcontactors, auxiliary switches each cooperating with a contactor andarranged to control the control circuit of a succeeding contactor, aconnection between each contactor and its auxiliary switch whereby whenthe former is open the latter is held open and when the lOlJllQl' isclosed the latter is permitted to close, an electromagnet theenergization of which depends upon the current in the power circuitarranged to prevent power circuit exceeds a certain value, and meansindependent of the magnitude of the current in the power circuit formaintaining the auxiliary switch open until the closing of thecorresponding contactor and until the increase in current in the power:ircuit, due to the closing 01" that 0011132101301,'lli$ taken place.

[Ofiim'cl Gazette May 14. 1918.]

connections in said power circuit, control the closing of said auxiliaryswitch it the current in the a L t ca;

Disclaimer in Letters P DISCLAIMER.

969,738.-Ha1-0Z(/ 12. White, Schenectady, N. Y. Cou'raoa OFELECTRICALLY- OPERATED SwrrenEs. Patent dated September 0, 1910.Disclaimer filed May 17, 1918, by the assignee, General ElectricCompany.

Enters this disclaimer- As to claims 1 and 19 of said patent, whichclaims read as follows:

1. In combination with a power circuit, a plurality of contactorsintended for operation in succession to cfl'ect certain connections insaid power circuit, auxiliary switches cooperating with certain of saidcontactors each arranged to control the 1 operation of a succeedingcontactor, means for holding each auxiliar switch open while itscooperating contactor is open, an electromagnet col'iperating with eachauxiliary switch for controlling the closing of said auxiliary switch,and means for maintaining the auxiliary switch substantially at restduring the closing operation of the cooperating contactor.

19. In combination with apewer circuit, a operation in succession toeffect certai circuits for said contactors, auxiliary switches eachcooperating with a eontactor and arranged to control the control circuitof a succeeding contactor, a connection between each contactor and itsauxiliary switch whereby when the former is open the latter is held openand when the former is closed the latter is permitted to close, anelectromagnct the energization of which depends upon the current in thepower circuit arranged to prevent the closing of said auxiliary switchif the current in the power circuit exccer s a certain value, and meansindependent of the magnitude of i the current in the power circuit formaintaining the auxiliary switch open until the closing of thecorresponding contactor and until the increase in current in the l power:ircuit, due to the closing 01' that contactor, has taken place.

[Ofiicial Gazette May 14. 1.918.]

plurality of eontactors intended for n connections in said powercircuit, control

